That is true, but still his pure efficiency has made Barca what they are right now. I don't think they'd be so strong without him. So it evens itself out if you ask me.
As for your second question, if its pace we're talking about, i sometimes think Zidane's lack of pace made him the technical mastermind, and visionary that he is/was. Pace might have ruined it for him, he might have played a different game(ie playing style).